Application of Fourier transform infrared spectroscopy (FT-IR) techniques developed at Battelle's National Center for Biomedical Infrared Spectroscopy to the rigorous modeling of protein- biomaterials surface interactions is proposed. The adsorption of plasma proteins onto biomaterials is generally recognized as an initial and crucial event that leads to thrombus formation. Despite extensive research, many fundamental aspects of the adsorption process have remained unanswered. The FT-IR method has a number of advantages over other methods such as the use of radiolabeled or fluorescein labeled proteins: 1) it provides real time adsorption information from protein solutions (single and mixtures) at physiological concentrations, 2) the adsorption experiments are conducted with aqueous solutions of proteins without any additional modifications and 3) it provides information about both the early and later events in the adsorption process, including any structural changes in the protein due to adsorption. We propose to study the adsorption behavior of plasma proteins as single components and from mixtures onto biomaterials with differing degrees of surface energy. The FT-IR information on the kinetics of adsorption and protein structural changes due to adsorption will provide the basis for development of a mathematical model of protein adsorption. We believe this model will provide molecular level information to understand blood-materials reactions. FT-IR offers a powerful method for non-invasively probing the interactions between blood proteins and biomaterial surfaces, and thus is a promising method for understanding the basis for the successful development of long term blood contacting prostheses.